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Major difference between GE (GFP-T) and GE (GFP-F) encapsulation modes at the client side of the TOM board

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GE (GFP-F) can detect and respond to negotiation packets of the Ethernet working mode. It supports autonegotiation. GE (GFP-T), like an optical fiber, implements negotiation of the Ethernet working mode between the data devices interconnected with the TOM boards.

GFP (an encapsulation protocol) defines two client signal adaptation modes:
Frame-Mapped GFP (GFP-F): GFP-F is a PDU-oriented processing mode. It encapsulates the entire PDU into the GFP payload area and makes no modification on the encapsulated data. It determines whether to add a detection area for the payload area, depending on requirements.
Transparent GFP (GFP-T): GFP-T is a block-code (8B/10B code block) oriented processing mode. It extracts a single character from the received data block and maps the character into the fixed-length GFP frame.

In the GE service mode, Ethernet port working modes are negotiated between WDM boards and client-side ports. In the GFP-T service mode, Ethernet port working modes are negotiated between client-side ports on both sides, and WDM boards transparently transmit negotiation signals.

In the GFP-T encapsulation format, client equipment connected to the TOA boards does not perform negotiation with the TOA boards. Instead, client equipment at two ends negotiates with each other directly. In the TTT-GMP encapsulation format, client equipment performs negotiation with the TOA boards.

In the GFP-T encapsulation mode, the client-side port does not perform negotiation with the TOA boards. Instead, client devices at two ends negotiate with each other directly. In the GMP-PPP encapsulation mode, the client-side device performs negotiation with the TOA boards.